I worded my post poorly. Obviously grafting foliage, thread grafting for nebari, etc are among many acceptable grafting techniques when done tastefully. It just seemed like white pines were the only species to get a pass for obvious root grafts, even when done cleanly.
Well, even then, some White pine grafts are better than others! Those will hardly noticeable grafts will be more valuable than those with an obvious graft.
Re the white pine on black stock grafts...
They graft the white on the black because the black pine trunk makes attractive bark much faster than does the white pine scion. The problem is the JBP trunk not only builds nice bark faster than JWP, it thickens, too. So, not only does the appearance of the bark change, usually there are large caliper change. So, the better trees are those where the caliper change is more gradual, or the graft Union can be hidden by a branch.